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In potentiometer experiment, null point is obtained at a particular point for a cell on potentiometer wire \( x \) cm long. If the length of the potentiometer wire is increased without changing the cell, the balancing length will (Driving source is not changed)

1. increase
2. decrease
3. not change
4. becomes zero

Correct answer: not change

Solution

In a potentiometer, the balancing length depends on the potential gradient of the wire and the cell’s emf. Since the driving source is unchanged, the potential gradient remains the same, so the null point stays at the same length.

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